I have a pond that I inherited with the house, along with a over-stocked amount of fish. The pond is about 4500-5000l of water that originally had a 2500l/h pump into a 4500l/h canister filter (it has sponges to mechanically remove waste) then back through a veggie filter to biologically remove waste chemicals.
After loosing a large number of fish a long time ago (came back from holiday and surprise had about a foot of water at the bottom). I've repaired a bonded corner of the liner by deepening the veggie filter and to complete replace the backing and liner.
Koi are 'messy' compared to goldfish (I have 4 mongrels plus other crosses of goldfish). It became obvious that the existing filtration wasn't large enough for the pond (cleaning the filter sponges every other day) so I replaced the canister with a 9000l/h sized canister with a 6000l/h pump. The reason is that for goldfish you only need a 1-2x multiplier for Fish stock length (ie head to tail of all the fish added together) vs the size of pond, and they are happy with the water being cycled at a slow rate. Not koi.. as they are messy - you're looking at half of those stocking figures (ie 1x) and the rate of water is 1.5-2x, so you're looking at trying to get a higher number of times/hour that the pond water goes through the filtration.
All of the above will be come important..
The mrs has, out of the blue, suggested we make a large pond away from the house (we want to replace the conservatory) and so the natural spot is the triange area towards the end of the garden. The existing pond is from 30cm to 1.20m deepest but it's quite constrained in more a v-shape cross-section. So the suggestion is to make it deeper. I have a "budget" but at the same time the first task is to compare realistically what it will cost vs the out of the air "budget" the Mrs has in her mind.. mainly to manage her expectations
So - this thread will follow my progress, through the planning the tradeoffs etc for creating a pond.
Task 1 - measuring to give rough ballpark figures.
I've measured up the existing area and the new area to get a rough idea. There will be a pond area and a filter area. I also have a couple of "requirements" - low maintenance (it should be able to run for two weeks without needing attention), it has the sound of running water (a waterfall that could be switched on/off) and that because it sits with an overhanging Hawthorn tree (and to help save the planet) no plastic liner and surface skimming of leaves/flowers/crap.
The measured area is a triangle/fan shape about 2.5m along the edges and about a good 3m at the front edge. There is a rectangle area about 1.2m x 1.7m that can be used for filter - it's close to the garage for power, drainage - both for floor of filter area and the flushing of the filters, plus I can run a water pipe underground to it.
This gives an approximate volume of water, depending on depth; 1.5m depth would be ~7500-8000l, 1.7m would be approximately 8500l. So we're looking twice the volume because of the steeper sides compared to the original pond.
I would also look to make a veggie filter that overflows into the pond via a water fall, also there will be returns via underwater jets - both should be designed to move any surface debris into the surface skimmers. There will be a 20cm wide border for walking around the sides.
So now we know - about 7500-8500l as the base will be sloping towards the 'bottom drain' where the water will be drawn into the pipe leading to the filter.
Thinking about filtration
The proposed filtration will work on gravity feed - so this means your pond and the filters sit water surface level. Then a pump sucks the water from the output side of the filter, and gravity then pushes the water from the pond into filter to compensate for the lack back pressure by itself. The benefit of this are:
* pump processes clean water only with perhaps a few fine particles thus doesn't bung up or reduce in efficiency.
* the waste from the pond is not macerated by the pump impeller before it gets to the filter, making the filter's life easier.
* If the pump fails then the filter does not empty back into the pond causing an overflow condition (a problem pump fed designs).
* The pump is not in the pond - this it makes maintenance easier.
So a 4" pipe connects the pond to the filters, then a smaller pipe then connects from the filters through the pumping and UV clarifiers back to the returns.
I want (for of requirements):
* mechanical filtration - removing the solids/litter before it gets further into the filtration
* bio filtration - that converts ammonia (fish pee) into nitrites then into nitrates
* optional mapping filter - this for fine particles but can be removed (they typically need cleaning every week or so) should I go on holiday without detrimental impact.
* veggie filtration - this is planted with "nitrogen fixing" ie also absorb ammonia/nitrites and nitrates into using bacteria in their own roots. The fine roots then also act to filter out fine particles.
* an ultraviolet clarifier - as the water passes though the UV light kills any single cell algae remaining and any parasites that may be wandering around the water.
* a drop of water to provide oxygenation within the pond (although a moving pond surface is the main mechanism for CO2 to escape and O2 to be absorbed)
* over flow protection - so rainfall that fills the pond over a set level flows straight to the drain, preventing an overflow.
* water top up - so if there is a hot day, or the filters are flushed etc then any drop in water level below a specific level causes water to be added to the pond from the mains.
* option for air in the pond to make the water move- this would be via a bottom drain with an air stone, the uplift of air to the surface causes water to flow so that the water at the bottom pushes waste towards the bottom drain.
* non-hands dirty cleaning - so simply move valves to clean the filters. No getting the filter out then using a jet wash to get the fish poop of my hands and sponges.
All this thinking means that it should look after itself without a regular maintenance other than a weekly or bi-weekly filter flush.
All the components should have ball valves rather than sluce valves as the sluce valves have a tendency to leak due to waste preventing a good seal. This means I can disassemble sections of the filtration without draining.
Equipment costs go up.. and we're looking at a decent sized filter for our pond..
There are many types of filters all promise perfection but in reality they have their own problems.
Pressurised canisters - these work but the larger the pond the more difficult they are, also they start getting a little difficult to keep clean and they don't provide the best biological or fine debris filtration. Also the pumps are usually macerating the waste before it gets to the filter..
My 9000l sized canister+pump was about £400-500 but has a way to switch the output to waste to allow cleaning without opening, after cleaning the output is switched back to the pond.
Multi-bay filters - these are chambers all joined together so the water flows from one side to the other. Each chamber has different contents designed for different things.. They are customisable but require regular maintenance as they use sponges, brushes etc to clean.. so it's mucky normally. The quality of filtration is often decent as long as they're maintained.They're reasonably cheap at £200-600 (without pump) depending on size, etc.
Sponge (also known as "jap-mat") are fine mats or media looking like sponges that trap debris, they need cleaning out by hand of the media to remove the waste. A variety of coarseness of the sponge means you can remove solids but also remove really small fines. They will block up and impede flow as they remove waste.
Moving bed - these use beds of moving medium (think if it as a bubbling cauldron) that have bacteria films on the media. They're good for biological filtering.
Static bed is like a moving bed but the media simply sits there a bit like a thick layer of sponge soaking up the debris. Then when they're cleaned, the filter is isolated from the filter path, then they're are backwashed or air washed to remove all the debris into the water - the water is then flushed to waste carrying the debris with it. The materials are anything from plastic media, to beads or even sand. The finer the media the harder it is to maintain flow rate, and as it becomes full the flow rate drops off.
Sieve - these are good for removing waste by simply passing the water over a metal mesh. the mesh can then be cleaned or flushed to waste. These are great at being a pre-filter to remove the larger mess, leaves etc. Unlike sponges the blocked waste sits on the surface and does not get buried into the sponge media itself. These are a ~£300-400.
Drum filter - these are the latest technology. They are fine mesh drums that self clean, they mechanically really remove lots of debris right down to fines. The system has an unbuildspray bar that cleans the drum as it rotates. The down side is that it constantly uses water to clean thus has a high water consumption. They're also expensive starting at £1200 but can easily get to £4000..
Skimmer - these sit at the side of the pond, the surface water continuously is sucked in and any surface debris or protein bubbles are held in the skimmer basket.
So going with my "low maintenance" approach I think the end goal will be pond--> sieve --> static --> moving bed --> UVC --> bay --> pump --> veggie filter --> waterfall>pond or pump--> return>pond.
Filtration cost...
So 7500-8500l volume you're starting to get into proper koi..
Thus the equipment would be:
* a skimmer will provide a tope level filtering that is returned back to the pond (this can be blended into the pump input).
~£160 for a wall skimmer, this requires a minimum of 6000l/h pump but would not need to be on all the time. I've got a 6000l/h pump on my existing pond and used the secondary input.
* a Nexus 220 will do a static and moving bed with simple valve turns to clean. It's maximum stated rate is 10,000l/h however reality is that a maximum of 8000l/h based on real world experiences. With a blended pump input with the skimmer then this rate can be tuned. It's not great at removing fines (nor is my existing canister).
Brand new this is £989, eBay £200. This requires requires an airpump, a normal pump and a UVC as none of those are provided. A new 70l/h air pump is ~140.
Then later.. the innards (the static bed) can be replaced with a Draco drum for ~1200.
* a UVC will cope with the flow rate - if not then two will have to be put in parallel to slow the flow rate, or if need be it can be partially bypassed. I would probably work this out at 8000l/h.
Now I have had a 7W in the old 4500 canister, a separate 18W (not really enough), and then a 24W in the 9000 canister (ie 6000l/h flow rate). I would suspect that 35W or even 40W would be needed to cope with the flow rate properly. £120-150 for a new 30-55W UVC able todo 15K-30K l/h. The more death the UVC can deliver to any bad organisms the better - the less likely they are to affect fish.
A small chamber with flow into japmat means any find debris or clumped algae caused by the UVC is cleaned but the the mats would require cleaning when in use. Hence the design it can be removed. This can be built out of fibreglass moulded, but if bought would be probably be ~£200.
Now the whole lot would need to be powered by a pump.. and they can be expensive to run.
EA Varipump 10,000 l/h is £175 but the pump can be set to run from 0% to 100% flow rate and shows the wattage used. Max wattage is 75W. My existing 6000l/h pump is 60W. This allows the pump to be turned down in winter when the fish aren't so active. The 20,000 l/h version is 190W but £225 and can be turned down to run at 20% in winter, then 50% for normal operation but then turned up if need be...
It's a rebadged Jebao which is a very well known and respected pump (they keep going.. 20+years).
Then you have the connections.. a 4" ball valve is ~£120..
Did I say it gets proper koi??
The Pond cost..
I don't want a liner and as the ground is simply sand which will shift, it really needs the water sealing to be fibreglassing with a flow coat. This means if the concrete or render cracks due to settlement of the sand then the pond remains water tight.
So.. the soil will need removing, and storing for refilling the existing pond. The filter area will need digging out to allow the filters to sit at the same water level.
Then the pond will need 4" of packed hardcore and then a 4-5" of rebarred concrete. Blocking will be put in for the walls (3' under the ground, 3' above ground) with a brick render on the front and capping the tops of the pond blocks.
The bottom drain and airlines sit in this concrete along with any returns that are routed under the pond.
The inside of the pond will then need rendering with concrete so it's smooth, and then sheets of fibre glass and resin are applied to make continuous barrier. 3 layers of fibreglass+resin are laid, so it covers up to the top of the blocks. Once dry layers of flow coat are applied to waterproof. The bottom drain is essentially fibreglassed into the base. As too is the skimmer at the side.
Any return Venturi is then installed.
Tops of block fibre glass is trimmed, and the top later for bricks are laid.
That's the pond done, so just adding the waterfall etc.
The filter house needs the brick/blocks, with a concrete base and a off run/waste drain set into the base. A top is needed, and then the equipment plumbed in.
Electrics are then added, also the water supply.
So this is currently what I'm about to start costing up. In short it may be cheaper to get a contractor in todo the pond construction in a set time period vs me taking months.
I've already checked the sewerage map to ensure there's no main sewer crossing my garden but there are local sewerage lines for gutters etc that may be found as we progress.
After loosing a large number of fish a long time ago (came back from holiday and surprise had about a foot of water at the bottom). I've repaired a bonded corner of the liner by deepening the veggie filter and to complete replace the backing and liner.
Koi are 'messy' compared to goldfish (I have 4 mongrels plus other crosses of goldfish). It became obvious that the existing filtration wasn't large enough for the pond (cleaning the filter sponges every other day) so I replaced the canister with a 9000l/h sized canister with a 6000l/h pump. The reason is that for goldfish you only need a 1-2x multiplier for Fish stock length (ie head to tail of all the fish added together) vs the size of pond, and they are happy with the water being cycled at a slow rate. Not koi.. as they are messy - you're looking at half of those stocking figures (ie 1x) and the rate of water is 1.5-2x, so you're looking at trying to get a higher number of times/hour that the pond water goes through the filtration.
All of the above will be come important..
The mrs has, out of the blue, suggested we make a large pond away from the house (we want to replace the conservatory) and so the natural spot is the triange area towards the end of the garden. The existing pond is from 30cm to 1.20m deepest but it's quite constrained in more a v-shape cross-section. So the suggestion is to make it deeper. I have a "budget" but at the same time the first task is to compare realistically what it will cost vs the out of the air "budget" the Mrs has in her mind.. mainly to manage her expectations
So - this thread will follow my progress, through the planning the tradeoffs etc for creating a pond.
Task 1 - measuring to give rough ballpark figures.
I've measured up the existing area and the new area to get a rough idea. There will be a pond area and a filter area. I also have a couple of "requirements" - low maintenance (it should be able to run for two weeks without needing attention), it has the sound of running water (a waterfall that could be switched on/off) and that because it sits with an overhanging Hawthorn tree (and to help save the planet) no plastic liner and surface skimming of leaves/flowers/crap.
The measured area is a triangle/fan shape about 2.5m along the edges and about a good 3m at the front edge. There is a rectangle area about 1.2m x 1.7m that can be used for filter - it's close to the garage for power, drainage - both for floor of filter area and the flushing of the filters, plus I can run a water pipe underground to it.
This gives an approximate volume of water, depending on depth; 1.5m depth would be ~7500-8000l, 1.7m would be approximately 8500l. So we're looking twice the volume because of the steeper sides compared to the original pond.
I would also look to make a veggie filter that overflows into the pond via a water fall, also there will be returns via underwater jets - both should be designed to move any surface debris into the surface skimmers. There will be a 20cm wide border for walking around the sides.
So now we know - about 7500-8500l as the base will be sloping towards the 'bottom drain' where the water will be drawn into the pipe leading to the filter.
Thinking about filtration
The proposed filtration will work on gravity feed - so this means your pond and the filters sit water surface level. Then a pump sucks the water from the output side of the filter, and gravity then pushes the water from the pond into filter to compensate for the lack back pressure by itself. The benefit of this are:
* pump processes clean water only with perhaps a few fine particles thus doesn't bung up or reduce in efficiency.
* the waste from the pond is not macerated by the pump impeller before it gets to the filter, making the filter's life easier.
* If the pump fails then the filter does not empty back into the pond causing an overflow condition (a problem pump fed designs).
* The pump is not in the pond - this it makes maintenance easier.
So a 4" pipe connects the pond to the filters, then a smaller pipe then connects from the filters through the pumping and UV clarifiers back to the returns.
I want (for of requirements):
* mechanical filtration - removing the solids/litter before it gets further into the filtration
* bio filtration - that converts ammonia (fish pee) into nitrites then into nitrates
* optional mapping filter - this for fine particles but can be removed (they typically need cleaning every week or so) should I go on holiday without detrimental impact.
* veggie filtration - this is planted with "nitrogen fixing" ie also absorb ammonia/nitrites and nitrates into using bacteria in their own roots. The fine roots then also act to filter out fine particles.
* an ultraviolet clarifier - as the water passes though the UV light kills any single cell algae remaining and any parasites that may be wandering around the water.
* a drop of water to provide oxygenation within the pond (although a moving pond surface is the main mechanism for CO2 to escape and O2 to be absorbed)
* over flow protection - so rainfall that fills the pond over a set level flows straight to the drain, preventing an overflow.
* water top up - so if there is a hot day, or the filters are flushed etc then any drop in water level below a specific level causes water to be added to the pond from the mains.
* option for air in the pond to make the water move- this would be via a bottom drain with an air stone, the uplift of air to the surface causes water to flow so that the water at the bottom pushes waste towards the bottom drain.
* non-hands dirty cleaning - so simply move valves to clean the filters. No getting the filter out then using a jet wash to get the fish poop of my hands and sponges.
All this thinking means that it should look after itself without a regular maintenance other than a weekly or bi-weekly filter flush.
All the components should have ball valves rather than sluce valves as the sluce valves have a tendency to leak due to waste preventing a good seal. This means I can disassemble sections of the filtration without draining.
Equipment costs go up.. and we're looking at a decent sized filter for our pond..
There are many types of filters all promise perfection but in reality they have their own problems.
Pressurised canisters - these work but the larger the pond the more difficult they are, also they start getting a little difficult to keep clean and they don't provide the best biological or fine debris filtration. Also the pumps are usually macerating the waste before it gets to the filter..
My 9000l sized canister+pump was about £400-500 but has a way to switch the output to waste to allow cleaning without opening, after cleaning the output is switched back to the pond.
Multi-bay filters - these are chambers all joined together so the water flows from one side to the other. Each chamber has different contents designed for different things.. They are customisable but require regular maintenance as they use sponges, brushes etc to clean.. so it's mucky normally. The quality of filtration is often decent as long as they're maintained.They're reasonably cheap at £200-600 (without pump) depending on size, etc.
Sponge (also known as "jap-mat") are fine mats or media looking like sponges that trap debris, they need cleaning out by hand of the media to remove the waste. A variety of coarseness of the sponge means you can remove solids but also remove really small fines. They will block up and impede flow as they remove waste.
Moving bed - these use beds of moving medium (think if it as a bubbling cauldron) that have bacteria films on the media. They're good for biological filtering.
Static bed is like a moving bed but the media simply sits there a bit like a thick layer of sponge soaking up the debris. Then when they're cleaned, the filter is isolated from the filter path, then they're are backwashed or air washed to remove all the debris into the water - the water is then flushed to waste carrying the debris with it. The materials are anything from plastic media, to beads or even sand. The finer the media the harder it is to maintain flow rate, and as it becomes full the flow rate drops off.
Sieve - these are good for removing waste by simply passing the water over a metal mesh. the mesh can then be cleaned or flushed to waste. These are great at being a pre-filter to remove the larger mess, leaves etc. Unlike sponges the blocked waste sits on the surface and does not get buried into the sponge media itself. These are a ~£300-400.
Drum filter - these are the latest technology. They are fine mesh drums that self clean, they mechanically really remove lots of debris right down to fines. The system has an unbuildspray bar that cleans the drum as it rotates. The down side is that it constantly uses water to clean thus has a high water consumption. They're also expensive starting at £1200 but can easily get to £4000..
Skimmer - these sit at the side of the pond, the surface water continuously is sucked in and any surface debris or protein bubbles are held in the skimmer basket.
So going with my "low maintenance" approach I think the end goal will be pond--> sieve --> static --> moving bed --> UVC --> bay --> pump --> veggie filter --> waterfall>pond or pump--> return>pond.
Filtration cost...
So 7500-8500l volume you're starting to get into proper koi..
Thus the equipment would be:
* a skimmer will provide a tope level filtering that is returned back to the pond (this can be blended into the pump input).
~£160 for a wall skimmer, this requires a minimum of 6000l/h pump but would not need to be on all the time. I've got a 6000l/h pump on my existing pond and used the secondary input.
* a Nexus 220 will do a static and moving bed with simple valve turns to clean. It's maximum stated rate is 10,000l/h however reality is that a maximum of 8000l/h based on real world experiences. With a blended pump input with the skimmer then this rate can be tuned. It's not great at removing fines (nor is my existing canister).
Brand new this is £989, eBay £200. This requires requires an airpump, a normal pump and a UVC as none of those are provided. A new 70l/h air pump is ~140.
Then later.. the innards (the static bed) can be replaced with a Draco drum for ~1200.
* a UVC will cope with the flow rate - if not then two will have to be put in parallel to slow the flow rate, or if need be it can be partially bypassed. I would probably work this out at 8000l/h.
Now I have had a 7W in the old 4500 canister, a separate 18W (not really enough), and then a 24W in the 9000 canister (ie 6000l/h flow rate). I would suspect that 35W or even 40W would be needed to cope with the flow rate properly. £120-150 for a new 30-55W UVC able todo 15K-30K l/h. The more death the UVC can deliver to any bad organisms the better - the less likely they are to affect fish.
A small chamber with flow into japmat means any find debris or clumped algae caused by the UVC is cleaned but the the mats would require cleaning when in use. Hence the design it can be removed. This can be built out of fibreglass moulded, but if bought would be probably be ~£200.
Now the whole lot would need to be powered by a pump.. and they can be expensive to run.
EA Varipump 10,000 l/h is £175 but the pump can be set to run from 0% to 100% flow rate and shows the wattage used. Max wattage is 75W. My existing 6000l/h pump is 60W. This allows the pump to be turned down in winter when the fish aren't so active. The 20,000 l/h version is 190W but £225 and can be turned down to run at 20% in winter, then 50% for normal operation but then turned up if need be...
It's a rebadged Jebao which is a very well known and respected pump (they keep going.. 20+years).
Then you have the connections.. a 4" ball valve is ~£120..
Did I say it gets proper koi??
The Pond cost..
I don't want a liner and as the ground is simply sand which will shift, it really needs the water sealing to be fibreglassing with a flow coat. This means if the concrete or render cracks due to settlement of the sand then the pond remains water tight.
So.. the soil will need removing, and storing for refilling the existing pond. The filter area will need digging out to allow the filters to sit at the same water level.
Then the pond will need 4" of packed hardcore and then a 4-5" of rebarred concrete. Blocking will be put in for the walls (3' under the ground, 3' above ground) with a brick render on the front and capping the tops of the pond blocks.
The bottom drain and airlines sit in this concrete along with any returns that are routed under the pond.
The inside of the pond will then need rendering with concrete so it's smooth, and then sheets of fibre glass and resin are applied to make continuous barrier. 3 layers of fibreglass+resin are laid, so it covers up to the top of the blocks. Once dry layers of flow coat are applied to waterproof. The bottom drain is essentially fibreglassed into the base. As too is the skimmer at the side.
Any return Venturi is then installed.
Tops of block fibre glass is trimmed, and the top later for bricks are laid.
That's the pond done, so just adding the waterfall etc.
The filter house needs the brick/blocks, with a concrete base and a off run/waste drain set into the base. A top is needed, and then the equipment plumbed in.
Electrics are then added, also the water supply.
So this is currently what I'm about to start costing up. In short it may be cheaper to get a contractor in todo the pond construction in a set time period vs me taking months.
I've already checked the sewerage map to ensure there's no main sewer crossing my garden but there are local sewerage lines for gutters etc that may be found as we progress.
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